1. Field
The present disclosure relates to a head-up display apparatus that displays vehicle information or navigation information to a driver by using a combiner.
2. Description of the Related Art
A known head-up display apparatus (hereinafter referred to as an HUD apparatus) includes a combiner and a light-emitting unit that are accommodated behind a dashboard. When the HUD apparatus is in use, the combiner is disposed so as to project from the top surface of the dashboard, and is illuminated with display light emitted from the light-emitting unit, so that a virtual image is displayed on the combiner, with the combiner arranged to be closer to the driver than the windshield is.
Japanese Unexamined Patent Application Publication No. 2012-254707 discloses an example of such a HUD apparatus. In this apparatus, a casing that houses a combiner and a light-emitting unit includes a top surface having an opening that enables the combiner to move out of and into the casing. When the apparatus is not in use, the opening is closed by two covers. When the apparatus is in use, the two covers are rotated in the opposite directions, that is, forward (toward a windshield) and rearward (toward a driver), and are accommodated in the casing, so that the opening opens. The combiner is moved so as to project upward from the casing through the opening. In this state, the combiner is illuminated with display light from the light-emitting unit through the opening.
In the HUD apparatus having the above-described structure, the two covers rotate in the opposite directions, that is, forward and rearward, to open the opening. Therefore, the operation of moving the two covers into the casing to open the opening and the operation of moving the combiner out of the casing so that the combiner projects upward through the opening can be performed simultaneously. Thus, when the apparatus is to be used, the combiner can be moved out of the casing so as to project upward in a short time.
However, the HUD apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2012-254707 has a problem that the overall size of the apparatus is large in the front-rear direction because one of the covers that closes a portion the opening through which the combiner passes needs to be retracted forward, and the other one of the covers that covers a portion of the opening through which the display light passes needs to be retracted rearward. In addition, since the cover that has rotated rearward to open the opening is accommodated in the casing, the design flexibility of the lower rear section of the casing is considerably reduced. Furthermore, the cover interferes with the installation space for instruments, such as a speedometer, that are disposed in front of the driver's seat.